Electronic storage of media is currently the preferred method of storing information. From non-essential phone numbers to top level government security information, magnetic media has been found to be secure as long as the magnetism of the storage medium is protected. For this reason the reliance upon magnetic storage mediums for storing all types of information is increasing exponentially. Should the storage medium be discarded, the ability for an unauthorized person to read such materials could be most damaging. Thus, the need to erase information from the storage medium has become of paramount importance.
While most computers could be repaired when they fail, technological advances and the low cost of replacement has made such repair uneconomical and most computers are simply discarded should a failure occur. During the discard process, the stored data is first transferred from the failed computer to the new computer. The hard drives of the discarded computer may be removed and the information stored thereon be erased. There are various devices employed to erase the information stored on hard drives but the most conventional is by degaussing to obtain reliable and complete erasure of the information contained on the hard drive.
Unfortunately, the finding of discarded electronic storage media still containing data is now common news. People believed the data had been deleted when a data storage device had been degaussed. Computers with information still in the memory have been sold or discarded. The high profile media coverage of some of these happenings and the potential liability and losses from such disclosures have made it more important than ever to provide extra security against such inadvertent loss of information.
While certain memory media may be easily destroyed, like optical memory, hard drives with rotating memory storage disks may be more difficult to degauss due to the housing structure. Hard disc drives typically include magnetic coatings rising past hard coercivities of 3000 Oersteds. The prior art systems using permanent magnets may not address the problems associated with degaussing of the newer type of hard drive components that are not readily accessible, due to such factors as the sealing of the hard drive disk and/or head within an enclosure having high coercivity magnetic media.
In order to properly erase U.S. Government classified magnetic media having a high coercivity magnetic media, erasure in as many spatial planes as possible is necessary. The applicant was granted U.S. Pat. No. 7,324,321 for a device capable of degaussing by use of a rotatable plate for rotating a hard disk between permanent magnets so as to expose the hard disk to various degrees of magnetism from various directions, the contents of which are incorporated by reference. A number of prior art devices that employ magnets for degaussing are embodied in patents such as U.S. Pat. Nos. 4,157,581; 4,286,295; 4,423,460; 4,551,782; 4,639,821; 4,757,419; 5,132,860; 5,666,413; 5,721,665; 5,979,774; and 6,714,398.
In many instances the act of degaussing must address the more difficult to reach hard disc media and/or remove signal data plus any residual magnetic noise if the disc is to be reused. The use of a capacitive discharge has been found to reach the more difficult hard disc drives and address extraneous or structurally generated magnetic noise pulses that might remain in the magnetic coating. The use of a capacitor discharge for degaussing is known in the prior art, see U.S. Pat. Nos. 2,838,720; 2,962,560; and 3,321,586 as illustrative examples.
Current teachings in this area have further found that the reversing of polarity improve the degaussing technique. U.S. Pat. No. 4,621,299 discloses a coil of wire having a substantially rectangular cross section in which a magnetic tape is inserted. A capacitor is charged and repeatedly discharged through the coil. A second capacitor is provided across which a control voltage develops. The voltage across the second capacitor is compared with the voltage across the storage capacitor. When the storage capacitor has charged to a level related to the control voltage, the storage capacitor is discharged at the same time the tape is rotated to reverse the field direction and ensure uniform degaussing.
U.S. Pat. No. 4,757,419 discloses an apparatus for generating pulse line of magnetic force using a diode in parallel with a first capacitor and a diode connected in parallel with a second capacitor, the capacitors have opposite polarity wherein the peak charge current required for the first capacitor can be reduced, and the capacitor discharge in opposite polarity.
U.S. Pat. No. 5,198,959 discloses a device for de-magnetizing magnetic recording tape. This device employs a cylindrical coil which is provided with exciting windings, the filed distribution of which extends essentially parallel to the winding plane of the recording medium.
U.S. Pat. No. 5,691,873 discloses a device for generating high-power magnetic pulses at shortened pulse intervals using multiple thyristors and a pair of coil members disposed to generate opposing magnetic fields when energized.
Thus, what is lacking in the art is a degaussing apparatus capable of housing a magnetic disc for subject to a capacitor based bi-directional degaussing current, the housing acting as a reflective chamber and allowing a pass through of the storage medium.